Effect of bark content on physical and mechanical properties of the kraft pulp from chips Populus deltoidsZinatFarhadiM.Sc., Dept. of Wood and Paper Sciences, Gorgan University of Agricultural Sciences and NaturalauthorAhmad rezaSaraeianدانشیار علوم و صنایع چوب و کاغذ، دانشگاه علوم کشاورزی و منابع طبیعی گرگانauthorMohammad rezaDehghani firuzabadiAssociate Prof., Faculty of Forestry & Wood Technology of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iranauthortextarticle2014perThis study was done to investigate the effect of bark content on the physical and mechanical properties of kraft pulp from chips Ppopulous deltoids. Three tree of the populous deltoids from the same age were randomly selected cut from Shastkalate research forest Gorgan. A disc was taken from each tree. The discs were completely debarked and wet weight of wood and bark from each disc was determined. Then weight ratio of wood/bark was determined in each disc. Kraft pulp was prepared under following pulping condition: sulfidity 25%, AA: 20%, temp: 170 0c, l/w: 6/1 and bark content as 0 , 6, 12, 18 and 24%, by weight. Pulp with kappa number around 20 was prepared from each treatment, which were separately beaten to reach freeness value around 350 ml,CSF. To determined the effect bark content on yield and kappa number of the pulp and their physical and mechanical properties, F test was used in completely randomized, and for comparison of the means, Dunkan test was used. Yield and kappa number of the pulps were as 50/32 - 52/03% and 20/37 - 21/17, respectively. With increasing, of the bark content, density of paper was decreased and the lowest value of which was 0/477 g/cm2for bark – contained pulp. Also, with increasing of the bark content to 18%, strength properties of the related pulp was improved.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014503514http://ijwpr.areeo.ac.ir/article_8473_aef6dbc3ffc7a6b5d68d31dfcbc9f327.pdfdx.doi.org/10.22092/ijwpr.2014.8473Improvement of printing and writing paper properties using PCC Filler Modified by cationic starch modified precipitated calcium carbonate fillerMoghadasehAkbariM.Sc. of Pulp and Paper Industries, Gorgan University of Agricultural Sciences and Natural Resources.
Gorgan, Iran,authorNadiaKabodi torabiM.Sc. of Pulp and Paper Industries, Gorgan University of Agricultural Sciences and Natural Resources. Gorgan, IranauthorHosseinRrsalatiProfessor of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, IranauthorGasemAsadpour atoeiAssistant Professor of Pulp and Paper Technology, sari University of Agricultural Sciences and Natural Resources, Gorgan, IranauthorMohammad rezaDehghani firozabadiAssociate Professor of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan,
Iranauthortextarticle2014perAim of this study is precipitated calcium carbonate cationic modification and comparison of impact of using its with conventional filler (unmodified) on strength properties of paper. One of the defects of adding fillers to paper is decreasing of mechanical strength of paper because of reduction in bonding area between fibers. In this study whit purpose of maintaining the strength of paper, and change the surface charge of precipitated calcium carbonate and replace it with conventional fillers are used.in this research with aim of precipitated calcium carbonate and replacing it with conventional filler was used. Condition of cationic precipitated calcium carbonate preparation was 90 ċ temperature, 3 hours time and 55% water content of cooking process. loading amount of starch was 9, 12 and 15 percent based on precipitated calcium carbonate weight.Papers made at three level: 10, 16, 30 percent of filler in paper sheets contain conventional fillers were compared. Results indicated that papers containing modified-filler have more values of retention rather than those with unmodified filler, both in 20% and 30% filler dosages.papers contained cationic filler have more mechanical strength index in respect of papers contained conventional fillers.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014515525http://ijwpr.areeo.ac.ir/article_8483_4b0f490f80d88aaaabc1a8a6f4cdcf73.pdfdx.doi.org/10.22092/ijwpr.2014.8483Effect of Nano TiO2 on Properties of Old Corrugated Paper Recycling Waste WaterSohilAmiriM.Sc., Wood and Paper Science and Technology, Karaj Branch, Islamic Azad University, Karaj, IranauthorAhmadJahan latibariProfessor, Wood and Paper Science and Technology, Karaj Branch, Islamic Azad
University, Karaj, Iran,authorSeid JavadSepidehdamAssociate Professor, Wood and Paper Science and Technology, Karaj Branch, Islamic Azad
University, Karaj, Iranauthortextarticle2014perOld corrugated container (OCC) recycling generates large volume of effluent which is heavily loaded with pollutants. Its treatment is very difficult and complicated due to the presence of various pollutants and certain chemical with complicated structure. In this study, the treatment of OCC recycling effluent using nano TiO2 was investigated and the treated effluent parameters such as COD, TDS, TSS, TS, EC and turbidity were measured. Nano TiO2 was applied at 0.5%, 1%, 1.5% of the effluent volume and the pH was adjusted at either 5, 9 or 7.3 (as received from mill). The results showed that the nano TiO2 and pH are effective on all of the parameters and the effect was statistically significant at 99%, but the effect of variables on EC was not measured statistically significant. The effect of pH on all of parameter was statistically significant at 99% expect on EC. Optimum condition was pH=9 and the dosage of nano TiO2= 0.5% and 1%. At this treatment condition, COD, TDS, TSS, TS and turbidity were reduced by 47.5, 38.7, 98, 70.4, and 97.7 % respectivelyتحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014526237http://ijwpr.areeo.ac.ir/article_8457_465142516f33d68ee45726a569cd1fef.pdfdx.doi.org/10.22092/ijwpr.2014.8457Studying on the Soda and Dioxane Lignin of Bagasse using Derivatization Followed by Reductive Cleavage (DFRC)vidahaji Aghaei, Master of Science, Payame Noor University, Tehran, IranauthorSeeyed AhmadMirshokraieProfessor, Department of Chemistry, Payame Noor University, Tehran, IranauthorTayyebepartoviAssistant Professor, Department of Chemistry, Payame Noor University, Tehran, Iranauthortextarticle2014perIn this study, the structure of Soda (soluble fraction in ethanol) and Dioxane lignins of bagasse were studied by using derivatization followed by reductive cleavage (DFRC) method and some techniques including gel permeation chromatography, gas chromatography-mass spectrometry and 13C-nuclear magnetic resonance spectroscopy and the results were compared. These comparative results show that the main monomeric compounds are obtained from the cleavage of β-O-4 bonds of lignins. The components obtained from Dioxane lignin and Soda lignin are guaiacyl, syringyl and p-hydroxyphenyl structures with different proportions. However, some differences have been observed in both lignins, including a variety of structural units in Dioxane lignin is greater than Soda lignin. In other words, soda lignin degradation and the structural components has become closer together and are more uniform structures. The average molecular weight of Dioxane lignin, is greater than Soda lignin, which is due to Soda lignin wide chemical degradation during industrial pulping processes and therefore it has less dense structure. These observations indicate that a mild method for lignin separation from a lignocellulosic material caused less damage and changes in lignin structure. Therefore, in structural studies, Dioxane lignin can actually be used as an appropriate representative of the lignin.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014538549http://ijwpr.areeo.ac.ir/article_8455_5ec766b455c4b38c16fb416bce2b8f79.pdfdx.doi.org/10.22092/ijwpr.2014.8455Shear and elastic moduli of Poplar wood affected by glue coverage deficiency of lamination in a vibration based nondestructive approachEhsanHaji rafirihaM.Sc., Wood and Paper Science and Technology, Karaj Branch, Islamic Azad University, Karaj, IranauthorMehranRoohniaAssociate Professor, Wood and Paper Science and Technology, Karaj Branch, Islamic Azad
University, Karaj, Iran,authorAhmadJahan latibariProfessor, Wood and Paper Science and Technology, Karaj Branch, Islamic Azad
University, Karaj, IranauthorAjangTajidiniAssociate Professor, Wood and Paper Science and Technology, Karaj Branch, Islamic Azad
University, Karaj, Iranauthortextarticle2014perThe effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied by non-destructive free vibration test. 120 samples with nominal dimensions of 2.5×2.5×45 cm without any obvious deficiencies were selected and free flexural vibration in free-free bars were performed for testing them. Samples were longitudinal cut in three thinner tangential layers and jointed together again using Poly Vinyl Acetate glue. The specimens were divided into four groups according to adhesive coverage rates, which one group was fully glued and 3 groups were carrying some glue deficiencies in different rates. Manipulated samples were tried again in above mentioned test. Results indicated that shear moduli compare to modulus of elasticity is a more sensitive parameter to evaluate glue efficiency in laminated beams but concerns remained due to blind points in flexural vibration nondestructive method.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014550560http://ijwpr.areeo.ac.ir/article_8458_59db67fea8ac33b2bd163c18c1581fbd.pdfdx.doi.org/10.22092/ijwpr.2014.8458Wood anatomy of an Iranian mangrove plant Avicennia marina (Forsk) VierthvahidrezasafdariAssociate professor, Department of Wood and Paper Science, Karaj Branch, Islamic Azad University, Karaj, Iran,authorshadmanPourmosaAssistant professor, Department of Wood and Paper Science, Karaj Branch, Islamic Azad University,Karaj, Iranauthortextarticle2014perThe Avicennia tree genus was named in honor of Ibn Sina, a 10th century Persian philosopher and physician known more commonly as Avicenna. In this paper wood anatomical property of Avicennia marina (Acanthaceae) which is one of the most important species of Iranian Mangrove forest has been investigated. Wood samples were taken from trunk of three adult trees, and and micro -sectioned and dyed by Astrablue and Safranin O and finally mounted by Canada balsam. Also Wood chips (match size) were placed in equal parts of glacial acetic acid and hydrogen peroxide and were put in the oven at 60°C for 48 hours, then counted and stained on microscope slides. The presence of concentric included phloem which is surrounded by lignified conjunctive parenchyma (axial parenchyma) and scleroid bands are the most important anatomical characteristics of Avicenna marina. The variability of anatomical characteristics of Avicennia marina in different references can be attributed to grwoing site condition (altitude and latitude).تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014561571http://ijwpr.areeo.ac.ir/article_8472_01551d928bb3d338b1d360bbe6400561.pdfdx.doi.org/10.22092/ijwpr.2014.8472Effect of wetwood and blue stain (Ceratocystis spp.) on the drying rate and fluid transport coefficients of poplar (P. nigra)ZibabFrozanMSc., Department of Wood and Paper Science & Technology, Faculty of Natural Resources, University of Tehran, IranauthorasghartarmianAssociate Professor, Department of Wood and Paper Science & Technology, Faculty of Natural Resources, University of
Tehran, IranauthorRezaGhamariMSc., Department of Wood and Paper Science & Technology, Faculty of Natural Resources, University of Tehran, Iranauthorhamedmatini behzadPhD. Student, Department of Wood and Paper Science & Technology, Gorgan University of Agricultural Sciences and Natural
Resourcesauthortextarticle2014perIn this research, the effect of wetwood and blue stain on the drying rate and fluid transport coefficients of poplar (P. nigra) was evaluated. For this purpose, five boards with dimensions of 150 × 35 × 45 mm were cut from wet‌ wood, normal ‌wood and stained -wood areas of freshly cut lumbers in Taleghan region and then dried to the final moisture content of 8 percent inside a laboratory dryer at temperature of 50 °C, relative humidity of 60% and air velocity of 1 m/s. Overall, drying time was 120 h. After drying, the transverse permeability and diffusion coefficients were measured. The results showed that the wetwood had no decreasing effect on the drying rate of poplar wood; however, it reached to the final moisture content slower due to higher initial moisture content. َAlso, the wetwood had no significant effect on the transverse permeability but reduced the diffusion coefficient. In contrast to the wetwood effects, the drying rate, permeability and diffusion coefficients were increased due to the blue stain.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014572580http://ijwpr.areeo.ac.ir/article_8469_5cbb07a768835294df335b50c34b84d2.pdfdx.doi.org/10.22092/ijwpr.2014.8469The influence of using waste PET on the mechanical and rheological
properties of wood flour filled PP compositesElhamOstadiM.Sc., graduated from Iranian Polymer and Petrochemical Institute, Tehran, IranauthorJalilMorshedianعضو هیات علمی پژوهشگاه پلیمر و پتروشیمی ایرانauthorYosefJahaniAssociate Professor in Iranian Polymer and Petrochemical Institute, Tehran, Iranauthortextarticle2014perIn this research the influence of using waste Poly Ethylene Terephthalate on the mechanical and rheological properties of wood flour filled PP composites has been studied. PET contents varied from 10-33 wt%. Mechanical properties were characterized by tensile testing, while their fracture resistance was determined by impact measurements. The melt rheological behavior of the composites was also studied by a rheometer in the oscillatory mode and dynamic rheological properties such as complex viscosity, storage modulus, loss modulus and damping factor were evaluated at190°C. The results showed that stiffness increases by adding waste Poly Ethylene Terephthalate. PET when added in low concentrations, caused tensile strength to be lower than that of PP composites filled with pure wood flour. Increasing the concentration of waste PET, led to composites with higher amount of tensile strength. The samples containing waste PET had higher complex viscosity and storage modulus than composite without PET. Likewise, it was observed that the damping factor in the PP/Wood composite decreased by incorporating waste PET to the compositions. Key words: waste polyethylene terephthalate, polypropylene, wood flour, mechanical properties, rheological behaviorتحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014581593http://ijwpr.areeo.ac.ir/article_8478_74ad7b516e4d6c2c3fac041112fdeab8.pdfdx.doi.org/10.22092/ijwpr.2014.8478MDF Production from Date Palm Pruning Residues in Pilot plant ScaleHosseinHosseinkhaniFaculty member, M.Sc., Department of Wood Science and its products, Research Institute of Forests and Rangelands, Tehran, Iranauthortextarticle2014perIran is not rich in forest land and only 7.5 per cent of country covered by forest. So Iran has to import wood based panel annually. It is estimated that 100.000.000 Date Palms trees covered an area at about 770.000 ha around world, and Iran has got 220.000 ha. Because of several reasons Date palm trees should be pruned and each tree produce 10-20 kg residues annually. In this study, for making boards Date Palm pruning residues as raw material and employed UF resin as the binder. Steeming time (5 and 8 Min.), steeming time (135 and 145oC) and press time (1, 2 and 3 Min.) were used as variable factors and three boards were made in Pilot plant scale for each combination of variables. Samples of all made boards were tested by the methods of EN to obtain mean values of bending strength, and Internal bond strength (I.B). In addition samples of each type of board were tested for thickness swelling after soaking in water for 2 hours and 24 hours respectively. The results of this study show clearly that boards have higher mechanical properties than the MDF property requirements which is recommended by EN standard.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014594608http://ijwpr.areeo.ac.ir/article_10619_843eadaa29774c4608440b7298a3a91e.pdfdx.doi.org/10.22092/ijwpr.2014.10619Fracture Behavior of Beech-Furan Wood Polymer under Mode IHamidehAbdolzadehPhD. student, Wood science & Technology Department, Natural Resources Faculty, University of Tehran, Karaj, IranauthorGhanbarEbrahimiProfessor, Wood science & Technology Department, Natural Resources Faculty, University of Tehran, Karaj, IranauthorMohammadLayeghiNatural Resources Faculty, University of TehranauthorMehdiGhasemiehAssociate Professor, Civil Engineering Faculty, College of Engineering, University of Tehran, Tehran, IranauthorSeiad AhmadMirshokraeiProfessor, Payame Noor University, Tehran, Iranauthortextarticle2014perIn this study, characteristics of wood-polymer fracture under mode I were investigated by double cantilever beam. In this regard, the properties of furfurylated specimens with three different levels of furfurylation (20%, 30% and 65%) were evaluated in both RL and TL systems. Results indicated that load-displacement curves from mode I fracture specimens were changed by furfurylation so that it was much clear on curves of TL system. These changes not only included curve slope in elastic and proportional limit zones, but also fracture zone and initiation of crack growth were included . Furthermore furfurylation and raising its content on both systems and especially on TL one, caused to change in stress intensity factor, KIC , and critical energy release rate , GIC. In both systems GIC were highly increased by increasing of furfurylation contents. This criterion demonstrated that the wood- polymer showed much toughness under mode I fracture. Moreover, variation of KIC values due to furfurylation at both systems was different with that of GIC. At the RL system, ascending trend was observed at KIC and GIC values by increasing furfurylation levels. But at TL system, KIC was decreased by furfurylation and this criterion enhanced by increasing of furan polymer in the cell wall. Generally, results of this research show that fracture toughness of wood is highly affected by furfurylation processتحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

2014623632http://ijwpr.areeo.ac.ir/article_8467_3b74d5629a3cf67e4f0d710613631fb1.pdfdx.doi.org/10.22092/ijwpr.2014.8467Nondestructive evaluation of dynamic properties in beach wood using free vibration method on free- free barmostafakohantorabi, PhD Candidate, Department of wood science and technology, College of agriculture and natural resources,
Science and research branch, Islamic Azad University, Tehran, Iran,authorFardadGolbabaeiFaculty member, Department of Wood Science and its products, Research Institute of Forests and Rangelands, Tehran, IranauthorHosseinHosseinkhaniFaculty member, Department of Wood Science and its products, Research Institute of Forests and Rangelands, Tehran, Iranauthortextarticle2014perIn this study effect of different NDT methods on dynamic properties in beech wood (flexural vibration and longitudinal vibration method) were evaluated .29 clear samples with nominal dimension of 2×4×36 cm selected and bending vibration in free-free beams and longitudinal vibration tests was performed on them. Results shows strong correlation between dynamic Young's modulus and acoustic coefficient measured with both Longitudinal vibration and flexural vibration method. Measuring damping factor values was significantly higher in flexural vibration compared to longitudinal vibration method, While the acoustic converting efficiency values from flexural vibration was smaller than values of this factor in longitudinal vibration method .There was good correlation between dynamic shear modulus of elasticity from flexural vibrations and dynamic modulus of elasticity in both methods, that it provides possibility of estimate the shear modulus of elasticity values according to dynamic Young's modulus of elasticity values from longitudinal vibration test.The results also indicated was a good correlation between the phase velocity in first to third modes from the bending vibration. In addition there was good correlation between sound velocity from longitudinal vibration and the phase velocity in first to third modes from the bending vibration.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014633643http://ijwpr.areeo.ac.ir/article_8468_509c10f7b6aa68de425a289fffcc4bf8.pdfdx.doi.org/10.22092/ijwpr.2014.8468Extraction, Identification and comparison of Organically chemical components in extractive of bark and wood from Eucalyptus by Gas chromatography - Mass spectrometrymiladtajikYoung Researchers and Elite Club, Chalous Branch, Islamic Azad University, Chalous, and M.Sc., student, Energy and New Technology Faculty, Shahid Beheshti Uneversity. IranauthorraminvaysiAssistant Professor, Department of Wood and Paper Science and Technology, Chalous Branch, Islamic Azad UniversityauthormajidkiaeiAssistant Professor, Department of Wood and Paper Science and Technology, Chalous Branch, Islamic Azad Universityauthortextarticle2014perThis research was carried out to identification and comparison of organically chemical component in the wood / bark extractives Eucalyptus camaldulensis. Three healthy trees were cut down from Nowshahr forest and samples were converted into the wood flour. The extractives was prepared with acetone solvent according to TAPPI standard, then transfer to the ballon and then the BSTFA catalyst was added and transfer to the GC / MS injections. Identification of components was done according to the retention time curve, calculation of Kovats correlation and Adams table. Out of 13 components in the bark of Eucalyptus and 18 components in that wood, 2 constituents such as Bis (2 - ethyl hexyl) phthalate and hexadecanoic acid was detected as the same. The most important of chemical component in the bark is (2 _ ethyl hexyl) phthalate (98.72 %). 2 - Pentanone (57.41 %) was important component in the eucalyptus wood .تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014644652http://ijwpr.areeo.ac.ir/article_8480_873e6fed4e486b040b31362372e75d99.pdfdx.doi.org/10.22092/ijwpr.2014.8480The effect ratio of adhesive urea formaldehyde melamine formaldehyde on the properties lightweight particleboard made from expanded polystyreneSamanehMirM.Sc., Student, Dept. of Wood and Paper Science and Technology, University of Zabol, Iran,authorSaeid rezaFarokh payamAssistant Prof, Dept. of Wood and Paper Science and Technology, University of Zabol, IranauthorMortezaNazerianAssistant Prof, Dept. of Wood and Paper Science and Technology, University of Zabol, Iranauthortextarticle2014perIn this study the possibility of using urea formaldehyde and melamine urea formaldehyde with different ratios of formaldehyde and melamine for manufacture lightweight particleboard by expanded polystyrene (EPS) was investigated. Experimental panels were made with 30 percent lighter that common particleboard in 25 millimeters thickness and with wood particles that had been came from a factory. Urea formaldehyde and melamine urea formaldehyde with two ratios different of melamine to urea, 40 to 60 and 20 to 80 were types of adhesive. Analysis of data and obtained averages on physical and mechanical properties indicated the best combination of EPS and used resins. Amino plastics adhesives showed good compatibility result with expanded polystyrene. As reducing of the weight of the panel was the most important target in this work, internal bonding (IB) result showed it was done. Because there was no any chemical reaction between EPS and phenolic resin as adhesive, it’s using was unsuccessful. Preliminary results especially internal bonding and physical properties revealed this lightweight panel is proper for defined applications. Furthermore, using melamine urea formaldehyde as adhesive was positive effects on IB and the highest IB was for the panel made with this resin and minimum EPS content. In comparison of common panels, this new panel with maximum melamine content and hydrophobic EPS showed better results on IB and physical properties.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329

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2014626635http://ijwpr.areeo.ac.ir/article_8471_f73e0c8f8d3dfe0ba8bd3422fbc698b4.pdfdx.doi.org/10.22092/ijwpr.2014.8471Effect of hydrothermal treatment on the acoustic properties of wood from Walnut and Elm species, utilizable in musical instrumentsMohammadGhofraniAssociate Professor at Department of Wood Science and Technology, Faculty of Civil Engineering,
University of Shahid Rajaee Teacher Training, Tehran, IranauthorHosseinHosseinkhani- Faculty member, M.Sc., Department of Wood Science and its products, Research Institute of Forests and Rangelands, Tehran, IranauthorHabibRahimi dastjerdiMasters Student at Department of Wood Science and Technology, Faculty of Civil Engineering, University of Shahid Rajaee
Teacher Training, Tehran, IranauthorSaeidKhojasteh khosroMasters Student at Department of Wood Science and Technology, Faculty of Civil Engineering, University of Shahid Rajaee
Teacher Training, Tehran, IranauthorParvizAmiriAssistant professor of electrical ENG-Electronic department in shahid rajaee teacher training UNIVauthortextarticle2014perThe objective of this study was to investigate the influence of hydrothermal treatment of walnut (Juglans regia) and caucasian elm (Zelkova Carpinifolia) wood species on their acoustic properties in radial and tangential directions. For this purpose, specimens were prepared with dimensions of 360 (L) ×20 (R) ×20 (T) mm. Heat treatments in water medium were performed at 150ºC for 5 hours. Acoustic properties of specimens (specific modulus of elasticity, damping, acoustical coefficient, acoustical conversion efficiency and wave velocity) measured by free flexural vibration on a free-free bar method. Properties of treated specimens compared with control specimens. Result showed that hydrothermal treatment improved all acoustic properties of specimens. Acoustic properties of radial and tangential surfaces of walnut wood did not show significant difference; while in caucasian elm significant differences obtained between radial and tangential surface properties. Generally, better acoustic properties achieved in tangential direction of heat-treated Caucasian elm species. So, it is recommended as a suitable specimen to be used in making the sound-boards of musical instruments such as Iranian Santour and Xylophones and also resonator boxes.تحقیقات علوم چوب وکاغذ ایرانموسسه تحقیقات جنگلها و مراتع کشور1735-091329